A Confounding Variable
by EnchiladaDan
Summary: A/B/O Dynamics. Case Fic. Alternate Universe. John and Sherlock have been living together for 5 months. Their statuses as an Alpha, Beta, or Omega are hidden from the world - and each other. But they have to come off the suppressants sooner or later, and the result surprises them both. Please do not read if you don't know what Omega-Verse is. Explicit Content.
1. Chapter 1

Sherlock Holmes and John Watson had been living (and working) together for five months now, if the October page of the calendar was to be believed. In this time, they'd gotten to know quite a lot about each other: John knew that Sherlock lived off of tea and nicotine patches during cases, and Sherlock knew that John didn't take sugar with his coffee; John knew that Sherlock indexed his socks by thickness, and Sherlock knew that all of John's underpants were white briefs… except for the lone part of red ones he kept tucked away behind his camo pants; John knew that (in between cases) Sherlock woke at seven, took his tea at eight, and his toast at nine. Sherlock knew that (between cases) John woke at six, showered at seven, and made breakfast at eight, before running off towards the clinic at nine.

And yet, for all the men _did_ know about one another, there was one thing they did _not_: Whether the other man was an alpha, beta, or omega. Not that it was a huge deal, of course; not in this day and age. Most people could go their whole lives not knowing who was what, especially when it came to the workplace. But the question needled at each of them, although neither was willing to volunteer the information first.

When John first met Sherlock, he was _sure_ the man was an alpha: he was loud, obstinate, and had a flagrant disregard for his own safety. He had a tendency to gesticulate wildly and was openly aggressive towards known alphas. However… the longer John knew Sherlock, the more convinced he was that he was a beta: he seemed to have this _need_ to prove himself, and his oft-stated disinterest in sex wasn't a common characteristic of an alpha. Although, when had Sherlock Holmes ever proven himself to be _common_? The only thing that John was fairly sure of was that he was most certainly NOT an omega.

Sherlock had not begun by wondering about John; in fact, it had been quite the opposite. He had deduced that John was definitely an alpha: strong, quick reflexes, ex-military; the whole thing practically screamed it. But then Sherlock noticed the surgeon's callous – the tough spot surgeons and other medical professionals often got along the inside of their thumbs from holding surgery shears – and he'd had to consider the question. With his medical training (and therefore, nurturing instincts), and the way he easily fell in line with Sherlock (or Lestrade) on a case, he easily came to the conclusion that his partner was a beta.

Not that there was anything _wrong_ with being a beta: their landlady Mrs. Hudson was one, as was Doctor Molly Hooper. Hell, even the lead in forensics, Anderson, was a beta.

But all that aside, the two men were sure: the other was definitely either an alpha or a beta, but neither was an omega. But, as it would turn out, they couldn't _both_ be right.

John was tired: they'd just finished a case and last night had been the first time he'd gotten more than a few hours' sleep in a week. But he knew, if he was tired, Sherlock must be _exhausted_; the man never slept during cases, and often crashed hard once the case was finally done. He padded down the hall to their shared bathroom, towel slung over his shoulder, when he noticed the door to Sherlock's bedroom wide open; the desk lamp was on, going by the strength of the glow spreading out.

'Poor bloke', he thought. 'He was probably too tired to turn it off.'

With this thought in mind, John marched up to the doorway, and stopped short: Sherlock stood at his dresser, cup of tea in one hand, and a small, nondescript oval pill in the other. He took it quickly, chasing it with the tea before he noticed John standing there, eyeing him curiously. Although the orange chemist's bottle had been blocked by the sleeve of his dressing gown, he quickly shoved it into his pocket, and stalked angrily towards the door.

"I thought you'd be sleeping, and had left the light on," John offered in explanation, and Sherlock's features softened a bit, although he was still headed towards the door.

"Good night, John," he responded with a note of finality, and shut the door in his face. He heard the lock turning a moment later. John sighed, and began to head towards the shower. He was used to Sherlock's rudeness when he was sleep-deprived, but that interaction had been just… strange. Shaking his still-sleepy head, he shrugged the situation off, and turned the doorknob to the bathroom.

A week later, John was in the kitchen making tea for the pair while Sherlock lounged on the couch, fingers gripping a recent medical journal – John's journal. "John, why do you still subscribe to these? Everything's online now – and it's _free_."

"If I did that, Sherlock, what would you do while you waited for Lestrade to text? What article are you reading, anyway?"

" 'The social implications of suppressant usage in betas'," he remarked, sounding haughty.

"Since you managed to get the post before I did, I haven't _actually_ read it… But yeah. Betas are tired of getting jobs recruiters think will be 'agreeable' to them. The new suppressants simply mask pheromonal markers, and do nothing to temper the mood. They're targeted towards alphas and omegas that don't do well on psychiatric meds, but want to keep their status secret. They're perfect for betas, actually."

Sherlock heard John's spoon stop stirring, as he placed the mugs on a wooden tray. "This secondary-gender discrimination thing can get pretty bad, or so I hear," he continued.

"The only con to suppressants is difficulty in finding a date," John answered, walking towards the living room. He chuckled a bit to himself.

"Bloody waste of time," Sherlock muttered, turning the page. "Just pick someone up, and let the chips fall where they may."

"And then get back to the flat, only to realize you're sexually incompatible? It's more than a bit embarrassing. Can you imagine if two _alphas_ took each other home?"

"Then they'd shag without worrying about pregnancy."

"Alphas can hurt each other if they try to knot. And if they get over that, it still wouldn't go over well with their loved ones."

"This sort of nonsense is why I'm married to my work."

As he set Sherlock's tea down in front of him, he glanced at his wristwatch. "Shit," he murmured with a sense of urgency.

He set his own tea down and quickly climbed the stairs toward his room. Intrigued, Sherlock followed him as silently as he could. The door to John's room was ajar, and Sherlock peered through the crack. John's side was to him, but an orange bottle sat on his desk, next to a water glass. He took a hurried gulp, tossing a small capsule into his mouth, before he shoved the bottle into his desk drawer. He leaned down to lock it and Sherlock took this opportunity to quickly run back downstairs.

By the time John reached the bottom of the stairs, Sherlock was sitting back against the couch, sipping on the tea that had been made for him. As John sat on his chair and sipped his own tea, Sherlock asked, "Problem?"

"No. Just… thought it was later than it was. Went to check my clock to be sure."

"Isn't there a clock in the kitchen?" Sherlock asked, pretending to be bored.

"There was… until you micro-waved it last week."

"That was for an _experiment_, John."

"I'm sure it was. But the fact remains that there is no longer a clock downstairs."

Sherlock chose to change topics, as he began to ponder why John had lied to him. "Breakfast?"

John shook his head. "We haven't time for much, but I'll make toast before I head out."

"Thank you, John. Orange marmalade."

"Yes Sherlock, I know." He sighed, and took his tea with him into the kitchen to make breakfast.

The desk had been a gift from Mycroft – it was _very_ well made. Sherlock wasn't able to pick it, despite trying for an hour after John had gone to work. He tried the other drawers, as well as the dresser in the corner of the room. Despite his (very careful) rifling, he couldn't find any evidence of what John was hiding from him. Sherlock huffed in frustration; he'd shown off too much. John was hiding what was probably ordinary cold medicine from him because he was tired of the detective butting into his business.

He balled his hands into fists and stalked out of the room, feeling indignant. Suddenly, his phone chimed. A text from Mycroft:

Six months is almost up. Shall I make the necessary arrangements? – MH

Sherlock scowled down at his phone, and typed out a quick reply.

Yes. – SH

Another text came almost immediately:

What will you tell Watson? – MH

He contemplated the question for a few minutes, becoming increasingly irritated, before shoving the phone back in his pocket in frustration. It buzzed a moment later, and he sighed as he checked it:

Two weeks from now, 11 am. I'll send a car for you… Minus Anthea. – MH

He wrapped his fingers around his phone, and he tucked it into the pocket of his dressing gown, before stalking off towards his room.


	2. Chapter 2

A week later, another case came: A portly, middle-aged man with shockingly orange hair sat in the arm chair, as John and Sherlock listened to him with rapt attention.

"Jabez Wilson," he introduced, holding out his hand. Watson awkwardly shook it. "I was hoping you would be willing to investigate a disappearance, Mr. Holmes."

_Beta. Diabetic. Near-sighted. Second-hand clothes._

"Family, pet, object?.." John started, noticing Sherlock was already beginning to look bored.

"None. A business, actually. One day, it just disappeared. No explanation, not a foreclosure sign or anythin'. Just a post-it saying, 'The Red-Headed League has been dissolved.'"

"If it's been dissolved," John asked, "why _exactly_ do you need us?"

"It's foul play, has to be. It's the only explanation."

Thus began a long narrative by Mr. Wilson, in which he detailed a business comprised solely of ginger-haired men.

"My assistant, Vincent, found it first: an advert in a local forum, asking for ginger-haired men with experience in transcription and research to update current databases for pay."

"Sorry, but why did the men need to be ginger?" John asked, not following.

"Personal quirk of the league's founder, Duncan Ross. He'd been turned down for many jobs, he said, because of his bright orange hair. Said they figured he was an immigrant from Ireland or Scotland, and that 'British jobs were for the British'."

"So he turned the tables, then. But if this was done online, couldn't anyone pretend to be so? Just doctor their photo or dye their hair?"

"He warded against that. Required multiple age photos, met candidates in person at the building, the 'Red-Headed League.' When we met he pulled my hair, to insure I hadn't worn a wig. He was an old coot to be sure, but he paid well."

"Go on," John urged, noticing Sherlock had perked up a bit at the last bit of information.

"I was paid to scan old medical journals, and to fact-check the 'ginger database' – an open source website related to all things ginger. I'd just finished fact-checking a page on gingers of note at the end of the week, and went to the League to collect my pay-cheque. Ross was keen on giving them to us in person."

"Us?"

"Me and the other blokes. There were two others when I started, although I seemed to be the only one as of late…"

"And your assistant, Vincent was it… at this time was?" John asked, hoping to get the man's mind back on track.

"Watching the business, of course. He does all right – even installed the buzzer feed to the basement so he'll always hear the door."

"Sorry, the basement?"

"Yes, the chap spends quite a bit of time down there. Photography hobby, see. He's made a dark room. Might be a bit much, though… he looks ill lately. Ought to see the sun more, I tell him."

Sherlock suddenly asked, "Have you a picture of your employee?"

The man reached into his jacket pocket and pulled out a flip phone. He scrolled through the contacts until he got Spaulding, Vincent and clicked on the name. A picture filled the small screen, and he handed it over.

Sherlock took the phone, committing the picture to memory, then handed it to John. He also looked at it carefully, before returning it to Mr. Wilson.

"He's always been a bit of a worrier, you see. Seems anxious lately, and only sees a friend or two on his days off. But anyway, he's nothing to do with this. When I went to get the cheque _that_ was when I saw the post-it."

"Mmm," Sherlock agreed, thinking. "So you said there were others – how do you know? Did you see them?"

"Well, no, not _exactly_," he began. "Mr. Ross told me, and another day, I saw cheques for them to pick up. He said he saw them less frequently, because they had laptops at home."

"And you don't?"

"No, just the old desktop, and I haven't been able to afford internet for some time. I've been doing all of my work for the league at the local library, about three blocks from my place. Bit of a pain to get to, really – no buses and a cab's out of the question, so I've been walking. On the plus side, in the last month I've lost about two stone."

"Congratulations," John remarked, his doctor's concern showing through momentarily.

He nodded in thanks, before Sherlock posed another question. "How long would you say you were out of your flat on a given day?"

"For the League, probably nine or ten hours a day; I would leave at seven in the morning and get back around five in the evening."

"And you wouldn't come back for lunch?"

"No, the dear boy would pack me a sandwich or two every morning while I read the news. I'd come home for supper, though."

"We'll look into it," Sherlock agreed, although the bored expression remained. "My associate, John Watson, will contact you when we've solved it."

"Thank you, Mr. Holmes. I look forward to it." He let John escort him out.

"All right, let's have it."

"Have what?"

"What have you deduced?"

"Not much… The man is a beta, although he spends a fair amount of time around a young alpha. Not a family member, no, there's no indication of that: no wedding ring, no mention of children. Most likely a stranger, someone he's employed – the assistant. He said he runs a small business, but it's not doing well. His clothes are second-hand, and have been tailored poorly to fit his large frame. The cuff on his trousers is one and a half centimeters higher on his left side than his right side. But considering he sits favoring his left side, the discrepancy cannot be from his posture. He's diabetic, and near-sighted."

"Diabetic?"

"He favors his left side because an insulin pump is clipped to the right side of his belt. He's a forgetful man by nature, which is one of the reasons he would opt for a pump. It also explains why he wasn't wearing his glasses, although it's obvious he wears them, going by the indentations on the bridge of his nose. Near-sighted because he'd notice he wasn't wearing them if he were far-sighted."

John's lips quirked into a smile: "Brilliant."

Sherlock just smiled, and gave him a wink.

John sat down and seemed to remember something as he looked around nervously, before starting, "Um, Sherlock?"

"Yes, John." He had reverted to his thinking position on the couch.

"I don't mean to… rush you, but do you think we'll have this wrapped up within a week? I have to visit Harry. It's… very important."

"Yes, of course. I, myself, will be away from Baker Street in a little over a week. Estate issues."

"So you'll be staying with your mum?"

"For a week, yes. I intend to wrap up our case work by then, and will pass this along to Lestrade. I will be quite unreachable during this time."

"I see. Well, I'll probably be at Harry's for a week, as well."

"I'm sure Mrs. Hudson will manage without us," Sherlock quipped.

"Right," John agreed, glad he didn't have to explain. Sherlock was usually in his face, asking or _deducing_ where he was off to at all hours of the day. But Sherlock seemed pre-occupied by his announcement. John wasn't going to look a gift horse in the mouth.

The next day, John and Sherlock found themselves outside the residence of Mr. Wilson. Sherlock circled the block, paying close attention to the alleyway between his flat and the next. He shined a flashlight along the foundation, before arriving at the doorway. He took off his gloves, and sprayed his palm with a small spray bottle, then knocked on the door. A few moments later, some clattering and cursing could be heard from inside, and the door opened.

_Alpha. Peaked appearance. Lost a stone since picture taken. Hiding something._

"Mr. Wilson isn't in," the young man answered, sniffing the air experimentally.

"Vincent Spaulding?" Sherlock asked, holding out his hand. The man shook it, then wiped his hand on his dirty slacks.

"_Sorry_, clammy hands. I just wanted to ask you where Mary's Fish and Chips is? Your neighbor Mr. Dortmund said you go there often, and I'm hopeless with maps."

"Just use your mobile, yeah? I've got work to attend to, mate." His eyes darted back to the house, and his brow creased.

"I'm a friend of Mr. Wilson's actually, and he said you'd be happy to help," John volunteered, realizing Sherlock was getting nowhere. The man started at this, wringing his hands together.

He began to gesture as he spoke and the detective noticed the dark grime under his fingernails: "Right… Turn left at the light, and then right on Edom for a block. Can't miss it."

"Thanks," John acknowledged, and started heading down the steps.

"Nice to meet you," Sherlock added, as he fell in line with John. The man closed the door behind them, and he heard a lock being turned.

Sherlock looked down at his hand, and frowned, before reaching in his coat pocket for a handkerchief.

"What was that, then?" John asked, watching Sherlock scrub the spot clean.

"Simple reagent test. Potato starch stains purple in the presence of iodine. I think I know why the red-headed league has been dissolved."

Within twenty minutes, Lestrade had been summoned to Jabez Wilson's residence. Lestrade turned toward the detective and said, "You had _better_ be right about this, Sherlock. We don't even have a warrant."

Sherlock just looked at him derisively. They rang the bell, and the bright-maned man answered the door. "What can I do for you, sir?" he asked, noticing the police car parked in front of his house.

"Detective Inspector Lestrade," he greeted, holding out his hand. The man shook it. "May I have a look inside?"

The man looked stunned, but opened the door. Lestrade walked through the doorway, followed by Sherlock and John. Several forensic workers trailed Anderson, who followed John closely. "Which door leads to your basement?" Lestrade asked, gesturing to the many doors in front of him.

Mr. Wilson tried one of the door handles and found it locked. He reached into his jacket pocket and extracted a pair of keys, unlocking both locks. He opened the door, and as he pulled the cord to turn on the overhead bulb, a noxious odor assaulted their senses. The man reeled back, getting a handkerchief from his pocket and covering his nose. Lestrade made a motion to Anderson, who ordered one of his workers to get masks. He came in carrying several respirators with an olive-colored stripe along each cartridge. They all affixed the masks, handing the spare to Mr. Wilson. As they descended, they could hear the hurried shuffle of feet along the unfinished floor.

When they turned from the staircase, Vincent was anxiously trying to unlock the clapboard door to the alleyway, a large rucksack slung over his shoulder. He was shaking and his hands were dirty from the hole he'd dug in the floor some ten feet away.

"Vincent? Oi! What's all this, then?" Mr. Wilson asked gesturing to the large baking sheets stacked in a corner, crumpled foil clinging to their edges, and an empty shoebox at the bottom of the hole.

The man attempted to jump through the window, but his arms were shaking and he missed the hand that was extended out to him from the other side. "Archie, help!" the man cried.

"_John_," Sherlock gestured, and John took the stairs up to meet Vincent's accomplice from the other side.

From the alleyway, they heard a loud "Oof!" John had tackled the accomplice.

"What's going on?" Mr. Wilson cried, as Sherlock bent down, using his gloved fingers to pull a small crystalline structure off of the tin foil. He held it up to the light, and retrieved an evidence bag from his pocket. After depositing it into the bag, he handed it over to Anderson, who was watching him curiously. Sherlock licked his finger, and made a face.

"Lestrade, arrest this man immediately. He's in possession of a Class A drug." By this time, Vincent had abandoned his futile attempt to escape, and was huddled in a corner, clutching the rucksack to his chest.

Lestrade's eyes widened and he moved forward, brandishing his handcuffs. After a scuffle, the man succumbed and the cuffs clapped his wrists. Anderson recovered the rucksack, and opened it. A gloved hand pulled out a large Ziploc bag of cloudy crystals, and a hush fell over the group. "You'll need to wait for lab confirmation, but I certain that what Anderson is holding is a kilo of poorly-dried methamphetamine. I'm sorry to report Mr. Wilson; contamination is probably the main source of your recent weight-loss. One really shouldn't let another make their meals… But on the plus-side, your headaches should cease once the house has been sufficiently aired out."

"But how did you know about the headaches?"

"The curious smell your jacket left on the chair in our flat, combined with your missing glasses clued me in. For one such as yourself, a beta, the irritating chemical smell might be mistaken for dry-cleaning treatment. And your glasses are new, meaning you're still getting used to the stronger prescription. But with the headaches cropping up after this purchase, it only made sense you would blame them."

"But I'd forgotten them when I went to your flat..?" he argued, still at a loss from all that had happened.

"That was how I knew they were new - indentations on the bridge of your nose. For a man that takes great pains to have his clothing accommodate him, I assumed the same would be true of your accessories. And your wristwatch proves it."

The man looked down at his watch, his confusion evident. "You've attached a band to the watch-face that you bought at the local chemist: A faux-leather band, although a watch of that type originally came with a metal cuff. Your joints swell after a hard day's work due to fluid retention caused by your diabetes and your wrists must pain you after typing for hours on end. Libraries aren't known for ergonomic design, leading to mild carpal tunnel."

He turned towards Lestrade and stated, "When I met Mr. Spaulding earlier this afternoon, my hand was damp with a potato starch solution. This reacts with iodine by turning purple. I hypothesized that his hands would have traces of iodine on them from handling the drugs without gloves. The drugs were manufactured and inadequately dried at Duncan Ross' before being transported to Mr. Wilson's basement for further drying and packaging. I believe Mr. Spaulding was the 'brains' of this outfit. Or, the closest you _can_ get to brains while struggling with a serious meth addiction."

He took a second to clear his throat, then continued: "The plan was clear – use Mr. Wilson's basement as a storage space for the drugs while Mr. Ross went about selling the product. They'd need the man out of the house, or he'd suspect something was up. Vincent knew Mr. Wilson was strapped for cash and they figured they could dip into the 'petty cash' to pay him. He used the ruse of a photography hobby to explain his lengthy visits to the basement. An unfinished basement is the perfect hiding place – just dig a hole in the ground to store the narcotics."

He gestured to the hole, which had since been markered off: "When Mr. Spaulding – not his real name, by the way – gave John directions to the chip shop earlier, I noticed the dirt under his fingernails. He'd been digging, probably hiding the newest batch. This was also evident from the dirty knees of his trousers, suggesting he'd been kneeling. I knew Mr. Wilson's flat had an unfinished basement as soon as he'd told me the address – all the flats on this block do."

"If Vincent Spaulding isn't his real name, then what is?" Lestrade asked, as John led the other man down the stairs. He began coughing immediately.

"Detective Inspector, I believe it would be wisest to finish this line of inquiry in fresh air."

Lestrade led "Vincent" out, with John still strong-arming "Duncan". Out in front of the flat, Lestrade motioned to the policeman arriving from a recently-parked car. The man moved to John, taking his captive and clapping cuffs onto him. He shoved the man into the closest police car and then pushed the other man into another car.

"The man that headed the red-headed league is not actually Duncan Ross, but a low-level criminal named 'Archie'. This is undoubtedly a nickname of Archibald Grossman, a street-chemist with one prior and a warrant out for his arrest. As I'm sure you've noticed inspector, he's gone to great lengths to conceal his true identity by growing a beard and dyeing his hair ginger. His employer, no doubt, has taught him how to do makeup, applying freckles and lightening his skin to add to the look. But he's not the one you should be interested in."

Sherlock turned to the recently arrived policeman and said, "Inspector Jones, correct? I believe we met once before, at Lestrade's last birthday celebration." The man gave a curt nod of recognition before he turned back to Lestrade.

"Detective Inspector Lestrade here has just caught the notorious John Clay," Sherlock remarked, and both inspectors' eyes went wide. Sherlock turned towards Mr. Wilson, and explained, "Don't be surprised you didn't recognize him – that was his aim. Color contacts, dyed hair, clean-shaven – not to mention the weight loss from his increasingly serious addiction… You couldn't have known unless you'd been looking. John Clay, as I'm sure you all have seen, is ordinarily a black-haired man with tan skin, blue eyes, a strong build, and a handlebar mustache. The man before you is a pale, thin, green-eyed man with no facial hair except for the mutton chops growing along his gaunt jaw. This man has hair that has been permed and dyed the most inconspicuous shade of brown. Unlike the handsome visage of the mastermind criminal, this man has a countenance most would go so far as to say is ugly: bent, bulbous nose and snaggle tooth. Those are prosthetics, I assure you. John Clay was classically trained in theatre and is thus quite knowledgeable of stage makeup and accents. His cockney tone is another lie."

He paused, and then addressed Mr. Wilson again: "You wouldn't be the first beta he's tricked, Mr. Wilson. John Clay is an embarrassment to Alphas everywhere, preying on the trusting and conciliatory nature of betas to accomplish his crimes. I'm sure testing of Archibald has told you he is a beta, as well?"

Lestrade hedged, "Well, yes… But Sherlock, that's classified."

"Not to anyone with a nose, I'm afraid," he replied, and winked. At that moment John Clay chose to cause a ruckus, banging against the window of the squad car with his shoulder. As attention was turned towards the criminal, Sherlock and John took the opportunity to slink away.

After they'd gotten a few blocks, John exclaimed, "That was… stupendous."

Sherlock smiled: "Was it?"

"Magnificent, really. And all that from dirty hands… Wow."

"Angelo's? My treat."


	3. Chapter 3

The week went quickly, and John came home from surgery to find Sherlock in his room. He had two suitcases: a small, rolling grey case, and a larger black one. The grey one had already been packed, and was situated near the wall. The black one was open on Sherlock's bed as he packed. John watched the spectacle in front of him with interest: it was different, this time. Usually, Sherlock was a dervish of hands and shirts, stuffing the closest things to him into the case. But now, he was slow, considering: He picked out the thickest socks he owned, even though it wasn't expected to be particularly cold; his hands moved to the back of his underwear drawer, drawing out a handful of silk boxer shorts and soft cotton pairs without fly buttons; he stroked each article of clothing, considering, before he packed it neatly into his case.

Given that he was going to the Holmes' manor, he was surprised when Sherlock took out at least a dozen t-shirts, and added them to his case. He pulled out three pairs of pajama pants, which was unusual as well; he'd been introduced to the fact that Sherlock slept naked when he'd ended up at the Palace in just a sheet. He walked to the closet, running his hand thoughtfully along silk shirts before pulling them out, and then he did the same for the black slacks hung up next to them. With a flourish, he pulled not one, but _two_ dressing gowns off hangers as he made his way back to the bed. It was at this time that he noticed John.

John recovered quickly: "Just wanted to ask what sort of take-away you wanted for dinner." He hoped he sounded casual, and not at all like he'd been watching Sherlock pack for the last five minutes.

"Chinese. The good place – run my card. I'm sure I'll be subjected to 'traditional British fare' while I'm away," he replied, the scorn evident in his voice. As John walked away, he heard Sherlock swear under his breath… Yes, Sherlock had been _very_ odd these last few weeks.

John sat in the living room, glancing at his watch occasionally to chart the progress of the Chinese food. They had said it would be an hour. Might as well catch up on his latest medical journal before Sherlock managed to set it on fire.

" 'Fecundity's Holy Grail: The Male Omega'," Sherlock read, over John's shoulder. He flopped down on the couch, and asked, "The Chinese is sorted, I take it?"

"Yep. I can leave to pick it up in twenty minutes. Have you read this one? It's quite interesting."

"I skimmed it. What I got out of it is most of that lot is sterile."

"That's true. But the ones that are fertile are extremely so. Although oral contraception is mostly prescribed for off-label usage, like mood management and reduction in heat symptoms."

"Hmm," Sherlock agreed noncommittally.

"The most popular ones decrease cramping and crying spells, among other things."

"You're just reading it off now, aren't you?"

"No, that's just my experience as a doctor. Although for every young male omega I see, I get three confused young betas. It seems sexual education has fallen to shit this past year."

"I shudder to think how ignorant I'd be if I had been forced to learn this sort of thing from my family."

Sherlock didn't elaborate, and John knew this was as far as he could push it without shutting Sherlock down entirely. He waited a few minutes then put the magazine facedown, open on the article. He laced his trainers and went to get the Chinese…

As the two relaxed in the living room, chopsticks digging into Lo Mein and Szechuan pork, Sherlock asked, "Aren't you going to pack, John?"

"Tomorrow," he answered, rooting around in his container for water chestnuts.

"Right … You're leaving the day after me."

"Mmm," he agreed, mouth full of food.

Later that night, Sherlock lay in bed, very much awake. He tried to sleep, knowing in two days he'd get none, when he was alerted to the sound of John's pacing footsteps above him. John hadn't done the pacing bit in awhile, and Sherlock, realizing sleep was a waste, quickly made his way upstairs. If John was up, he figured they could go over cold cases together.

As he neared John's room, he heard John bark out in a hushed tone: "What do you _mean_ I can't stay there? Harry, this is important!"

He listened for a minute and then replied, "'Not safe'? We've had this worked out for months. Christ, I – yes, Sherlock will be gone. That's not the point!"

He listened for a moment more, then sighed: "Good_night_, Harry."

Sherlock knew a sibling squabble when he heard one. He quickly walked downstairs, and decided to tackle his cold cases alone.

The next day, Sherlock wheeled his black suitcase into the living room, while John sat curled on the couch, typing on his laptop. "Ah, the 'red-headed league'?" he asked, as John typed quickly.

"Hmm? Yes, just putting the finishing touches before I pack."

"Pack? You're going to pack?" Sherlock asked slowly, uncertainly.

"Yes, I've put it off long enough," he replied, eyes glued to the computer screen.

"You know John, if anything should happen, and Harry needs a place, she can stay while I'm away. You can take my bed, since I won't be needing it." He had hoped broaching it this way would get John to confess what had happened with their row.

"Oh, um, thank you, Sherlock. I'll be sure to pass it on." With that he closed the laptop, and tucked it under his arm. A horn honked outside, and Sherlock started. John held out a hand, and Sherlock shook it.

"See you in a week," he said, and John nodded. He waited until the town car was out of sight before he flipped his laptop back open. He'd been looking for cheap motels nearby, specifically those that catered to rut/heat needs. He was having trouble finding anything secure enough for his price range. He sighed, and typed a new phrase into the search engine: "pick up/drop off laundry service", and typed the number into his phone.

"Yes, hello? I wanted to inquire about prices for a pick up/drop off service to Baker street?" He paused to listen.

"Yes, and I have a few more questions: is there anything you don't treat? I see – no, nothing like that."

He could feel a blush creeping onto his face as he asked, "And all your delivery workers… are they-" He took a breath, before relief washed over his features. "Betas? All of them? You sure? Excellent."

"Thank you, that's all for now. I'll be ringing soon, then."

He clicked the phone shut, and was on his way to the kitchen to make himself a cuppa when a sudden pain punched low in his gut. '_No_,' he thought, his heart racing, 'this isn't supposed to happen until tomorrow…'

With shaking hands, he hit redial: "Yes, hello, I just spoke with you? I'd like a pick up/ drop off at the end of this week to 221B Baker Street." He gave his credit card information, and hung up, breathing shakily. He pulled a cloth bag out of the pantry and went upstairs as quickly as he could.

_Not safe, not safe, NOT SAFE._

He scented the air: Mrs. Hudson downstairs – beta; Mr. Robinson upstairs – beta; Ms. Fenton next door – omega. In fact, the closest alpha was out on the street below, a policeman.

Logically, he _knew_ he was safe. But the other part of him, the more primal part, didn't feel it. He closed the door behind him, locking it tight and quickly went through his closet, pulling out provisions: the cloth bag contained food and water, since he doubted he'd get much chance to leave his room; he yanked out his softest terry cloth robe, although he knew he wouldn't be able to stand even that after the first day; he pulled out slippers, noise-cancelling headphones, a dehumidifier, a fan, extra blankets, and every towel he owned.

He began rifling through his drawer, checking his prescriptions and assuring himself he'd taken what he needed to. He pulled out a large bottle of paracetamol, along with an eye mask, a box of gloves, and a thermometer. He moved all of these to the night stand and unmade his bed, knowing he'd be holed up here for a week.

Across town, Sherlock sat in the back of the town-car uncomfortably. He pulled at his collar, suddenly too hot. He looked down at his shaking hands, shifting to accommodate his slowly-growing erection, the fabric of his suddenly-uncomfortable slacks straining.

"Stop the car. I need in the boot."

The driver stopped and Sherlock bolted out, making his way to the popped door. He stared in horror at the boot's contents: a single black suitcase. He'd forgotten the grey one.

STUPID! _How_ could he be so daft?!

He closed it quickly and got back in. "Turn around. I've forgotten something very important at 221B."

Back at the flat, having arranged his room properly – windows blacked out, appliances set up, bed arranged - John stood in the shower, trying to get clean as quickly as possible. He'd had a shower just that morning, but considering the way his brain was fogging up, he knew the other physical signs would come soon. Best to get a shower in while he could still manage standing.

Once he was out, he shaved quickly, and was reaching for his aftershave when he remembered: the aftershave that was usually so agreeable to him was an absolute assault on his senses when he was off his suppressants. He shook his head and brushed his teeth, feeling the prickle of a fever beginning under his skin. At that moment, he wished he was a beta; only alphas and omegas had to deal with the feverish delirium of their hormones. He spit into the sink, and quickly made his way upstairs, towel tucked tight around his hips. He managed to make it to his room, and locked the door before he felt it: he was sweating in strange places, whereas everywhere else was bone-dry; his scalp and the back of his neck began to sweat, and he could feel himself begin to get hard. As he tossed the towel aside, he caught a glimpse of himself in the mirror on the closet door: his cheeks were slowly reddening, and he had a flush from his neck down to his belly-button. He tore his eyes away, and got under the covers, taking as many of the pills as he safely could to curb his worsening fever. His senses were becoming keener by the minute, but his brain was sluggish, working at half-speed.

"Drive. _Faster_," Sherlock snarled, unable to contain his irritation any longer.

"Sir, we're still 20 minutes from Baker Street. Should we get pulled over, I doubt you'd be able to make it the rest of the way in your … condition." The driver pushed a button and the partition came up, as Sherlock spewed abuse at him.

What had made it worse was that the driver was right: Sherlock was sweating, close to fever, and soon he'd feel the tell-tale pheromone sweat on his neck. He unbuttoned a couple of buttons on his silk shirt, his skin radiating heat, and turned the air conditioner up. As long as he could get to the case soon, he didn't care if he ended up "soiling" the backseat in a hormone-fueled sex haze.

His hands were shaky as he typed out a text:

If at home, please place grey suitcase by door. – SH

He waited anxiously for John's reply, but it never came.

John could hear his phone buzzing from his desk – it was so _loud_. But by this point, his legs didn't seem to want to work. Sherlock had said he'd be unreachable, so he pushed the thought from his mind. If he could just _try_ to sleep, he'd be saved from this misery for an hour or so.

He knew his efforts were in vain: the only thing that brought on sleep when he was like this was sexual exhaustion; and even with John's best efforts, without fulfilling his urges _properly,_ he was looking forward to a lot of sleepless nights. Despite this, he might as well give it a go: he took his cock in his hand and stroked, but the feeling wasn't enough. Luckily, John was more prepared this time than the last; with his free hand, he opened the drawer to his nightstand, and reached inside.

The town car stopped in front of 221B abruptly, and Sherlock bolted from his seat. He scrambled with the keys, ignoring the concerned look from Mrs. Hudson as he rushed towards the stairwell. He took the stairs two at a time, ignoring the ache in his groin from his insistent erection. Dropping his keys, he cursed and picked them up, hands still shaking. It was setting in much more quickly than anticipated. He opened the door, and as he pushed in, an unfamiliar scent assaulted his nose. He looked around, trying to assess the situation as he walked up to his room, but he felt himself getting slow. Just as he crossed the threshold and spied the case, he placed it: natural scents – seawater and juniper – underlay a spicy scent, something even Sherlock wouldn't have been able to detect, were he not in his current condition. There was unmistakably the scent of John, too: earl grey and wool jumpers flooded his senses, almost as an afterthought.

John must have company.

Sherlock knew it was dangerous to stay here in this state, but his curiosity got the best of him as he took the stairs, case forgotten. It wasn't until he got to John's door that the full reality of the situation set in: he was smelling an omega, _in heat_.

His hands shook and his mouth watered at the prospect, as he forced himself down the stairs. He had to get out of here, fast. He grabbed the case and was almost to the door when he heard it – or rather, _didn't_ hear it: John moaned loudly, unable to control himself. But there were no other moans, no pants. If John had an omega in there, in heat no less, he or she wouldn't have been able to keep quiet for the life of them.

John was alone.

Sherlock dialed quickly: "Go back. I'm staying here."

He clicked the phone shut, and took the stairs again. The close proximity to an omega had renewed his vigor and he grabbed at the door handle, frustrated to find it locked. He took a deep breath, the scent making the hairs on the back of his neck stand on end.

"John," Sherlock intoned, his voice coming out between a growl and a purr. When John failed to respond, he banged on the door. "John, are you all right?"

His protective instincts came to the forefront of his mind. John was hurt. An _omega_ was hurt.

It took him a few tries, but Sherlock kicked the door in. The room was dark, and it took a few moments for his eyes to adjust. In this time, John scrambled into a sitting position, heart racing. He ripped the obviously too-effective headphones off of his head, and curled the blankets tight around him, although by this point he was sweating bullets.

Sherlock's keener ears perked up in response to the sound of a clatter against the floor; his eyes roamed, making out the sex toy that had fallen out from John's covers: it was a large toy with a flared base and a knot-mimic, and looked slippery. He looked back at John, whose expression was quickly morphing from mortified to enraged.

Sherlock's nostrils flared, taking in the strong scent of the omega before him. Although John's usual tea/jumper scent was often unobtrusive it now radiated off him, the natural omega scent mingling underneath it. As his wide pupils took in the altered scenery of John's room, John seemed to find his voice:

"Sherlock?! BLOODY HELL! _Get. Out._" His voice came out hoarse, a combination of raspy pants and low threats.

"You're an omega." Sherlock accused, as he stepped closer. Normally, he'd heed John's warning, not wanting to be on the bad side of that temper. Now, however, he couldn't help but find it intriguing.

"Oh, sod off you damn – _oh_." John sniffed the air experimentally, not sure he could trust his senses. He smelled Sherlock – starched silk and loose tobacco – but the scent below that… It was unlike any alpha he'd ever smelled: he smelled like dark roast coffee and no, it couldn't be. _Sugar?_ John had heard omegas were supposed to smell sweet, but never an alpha. John's skin was practically buzzing, his fingertips yearning to touch the man before him. His hole throbbed, slick leaking from it down into the sheets below.

"You're not a beta."

"No … of course not. Why would you think that?" Sherlock still advanced slowly. All of his previous knowledge of the aggressive ones warned him omegas were flighty, twitchy.

"Not safe," John managed petulantly, although his hands let go of the cover around him. One particularly deep breath, and he'd be exposed from the waist up.

"I … you're an _alpha_," John finished, his brain fogging over again as a second wave of heat hit him. His treacherous body was shaking from the proximity of the fit, virile alpha before him so obviously in rut.

"I am …" Sherlock's restraint considering the circumstances was incredible; John felt the anger and annoyance over the violation of his privacy fade slowly, as he let his baser instincts flood his thoughts.

"You can help…" John drew the covers away from his body. His sex flush had gotten worse, and his nipples were dark and peaked; his cock was achingly hard, although he'd just cum; he spread his legs, and the smell of slick became overwhelming.

"John, I … it's not safe. You'll get pregnant. I might try to bond you…" Although Sherlock shook his head, he sat on the edge of John's bed, chest heaving as he breathed in his scent as he toed off his shoes.

"It's fine, on the pill …"

"_John_," he nearly-moaned, as his hands reached towards the remaining buttons on his shirt, "are you sure?"

John reached forward, and grabbed his lapel roughly. "I _swear to God_ Sherlock, if you don't plough me into the mattress and knot me, you'll be sorry."

"For fuck's sake, John," Sherlock replied in reverence, and gave up on the buttons, instead ripping his shirt off.

He ruffled his hair, scent oils contacting his hands, and pressed them to John's shoulders. Sherlock gripped him hard as John's hands worked his fly open. He tugged insistently on the trousers, and Sherlock pushed them down, along with his boxers and socks. Sherlock climbed over to him, between his legs.

Looking down at John's sizeable cock, Sherlock was so far gone he barely managed to get out the question: "Safe word?"

"No, we don't need-"

Sherlock interrupted, barking out, "Tell me or I can't let myself touch you!" His eyes were wild, and his hands shook with the effort of keeping them from roaming.

"Um... Liverpool," John complied, the effort of thinking nearly painful at this point, as he keened his hips upward.

With that, Sherlock closed in on him, bending his legs back towards his chest. He pushed a finger experimentally on John's hole, and slick leaked out, coating the digit. He brought it up to his mouth and licked it; his eyes grew dark, light irises eclipsed by pupils. He pressed the head of his cock against the slick pink hole, John making a positively submissive noise in the back of his throat. The alpha in Sherlock preened at this, growing possessive as he took John by his hips. With one great thrust, he bottomed out inside John, who stifled a cry.

Whether it was from surprise or pain, Sherlock couldn't be sure. He held the omega close, his rut warring in him to move, while his alpha instincts bared their teeth right back, ordering _protect_. He nuzzled his nose behind John's ear, and he heard John utter, "_Make good on your promise_ _alpha, and knot me_."

Sherlock's hands moved quickly back to his hips, and began to move. The feeling was overwhelming, tight and slick and throbbing and so perfectly _made_ for him. His delicate fingers gripped John's cock in his hand, and stroked in time to his thrusts. John was supple underneath him, his back bending to arch upward, craving as much skin contact as possible. His skin was soft and hot, sliding along the paler man above him.

Sherlock's thrusts were careful, measured. When John's eyes met his, he was startled by the look of concentration they held; how could he focus on _anything_ when this feeling was so perfect? The brief pain was now gone, eclipsed by overwhelming pleasure. He felt himself spasm and clench around the alpha, a dry orgasm wracking his body as his fingers dug into the pale back above him.

Their eyes met again, and the look was gone. Sherlock looked like someone had just knocked the air out of him; his eyes were wide and his mouth parted in some unheard cry. His disheveled hair and the way he panted "_John_" were too much for him: With a strangled cry of "_Sherlock!_" John came, pulsing in Sherlock's hand.

The heady scent this added to the room was driving Sherlock crazy: "_Oh God, yes… John_," he moaned when he felt clenching around him.

He could feel his cock getting even harder, a sign his knot would be swelling up soon. John moved his hips just so, so the head of Sherlock's cock brushed his prostate. He threw his head back as a third orgasm was forced out of him.

The wild look in Sherlock's eyes returned, and he took John's hands from his back, and pinned them above his head. John struggled in earnest, but the alpha's strength rivaled his. Sherlock was babbling incoherently as he thrust deep into John, his knot beginning to swell: "…knot you omega, claim you as my own… _make you my bitch_…"

Anger flared in John's core, and flashed across his eyes. He linked his ankles together behind Sherlock's back, and broke the hold he had on his wrists. He grabbed Sherlock's back and rocked to the side, flipping them over. Sherlock was still thrusting in and out as if none of this had happened, his knot catching on the rim as it continued to swell. Soon, he wouldn't be able to move at all. John moved his feet to get more comfortable, and pinned Sherlock's arms to the bed.

"John H. Watson is _no one's_ bitch, you got that?"

The effect his expression had on Sherlock was astounding. He recanted immediately, nuzzling into John's neck and murmured, "…just want you so bad, _only you…_ not share you…"

He made a low whine in the back of his throat, the closest alphas were able to get to begging in this state, and with a final push, he seated his knot inside John.

The stretch against his walls burned, a spike of pain as he shifted to get comfortable against Sherlock's chest. He gazed down at the alpha just in time to see him come: Sherlock's eyes, which had been clenched tight as John rode through his orgasms snapped open. "_JOHN!_" He howled, words dissolving into small keening noises as his orgasm ripped through him.

John could feel himself being filled, this heat new and overwhelming. As Sherlock tried to thrust even as they were tied together he bent his head up, nuzzling against John's neck again. He breathed in deeply, scenting him. He broke the grasp John had on his arms and pulled John even closer, hugging him tight.

His eyes darkened further, and he licked briefly before he sunk his teeth into the tender skin of John's neck. John yelped at the sudden pain as Sherlock bit down, but he didn't fight. John knew a bonding bite only took if both parties wanted it, and despite everything that told him to resist, he wanted it. He must be mental, but he absolutely wanted to be Sherlock Holmes' mate. When Sherlock let off, he leaned back, John catching a momentary glimpse of blood on the tips of his incisors.

Sherlock lay back against the bed, turning his head to offer his neck to John in return. John leaned down, scenting his skin for a moment. He wanted to savor the scent of Sherlock, knowing his scent would change to John once he bit. He nuzzled against his neck, trying to find the best place to mark. His instinct welled up in him again and he licked the spot, a warning. His lips closed over the spot and he bit down. With his teeth sunk into the pale column of his throat, something changed. He bit hard enough to scar, tasting blood on his tongue. He held his jaw there for a moment, before slowly releasing his hold. When he came off, he felt different. His head was foggy like before, but it was not unpleasant.

He loosened his hold on John's back, and his hand sought John's. He laced their fingers together and they turned, each nuzzling in the crook of the other's neck. After awhile, John felt the knot inside him begin to shrink, and he was able to slip free. He shifted, settling in against Sherlock's side before falling asleep.


	4. Chapter 4

The rest of the week proceeded in much the same vein: they'd sleep for a few hours, and then be jolted out of a deep slumber by arousal that required the other's warm body to quell. Despite John's medical knowledge, the two flat-mates bonding one another did nothing to shorten their respective cycles, although the intensity decreased with each passing day. By the 7th day, they were down to mating once a day.

After the last wave passed them, and they lay spent against the bed, Sherlock turned to John and breathlessly asked, "What now?"

"We'd better spend the night together, lest we get separation anxiety from the bond."

"Separation anxiety? I'd be right downstairs," Sherlock argued, incredulous.

"This is the last day of it. After that, we can sleep wherever we choose. I know you're keen to be alone Sherlock, but remember _you're_ the one who broke down _my_ door."

"Don't be silly, John. I wouldn't have bit you if I hadn't wanted to be with you. As I've said before, I'd be lost without my blogger." John smiled at him, searching the sheets for Sherlock's hand.

"But let's let the internet figure this one out for themselves, shall we?"

"Of course, Sherlock." They fell asleep soon after that.

The next day, John woke to an intensely bright room: Sherlock had stripped the windows of the black-out curtains, and the sills were cracked, letting in a warm breeze. He looked around, disoriented. He'd gotten used to Sherlock sleeping like a log at his side, his curly hair skewed across the pillow as he curled around John. But now the space was empty, although the bed still held an impression – he hadn't been gone long.

John stood up and stretched, feeling the strength returning to his sore muscles. His neck had a painful kink in it, and his arse ached something awful. He grabbed a dressing gown from across the room, and slowly made his way downstairs. He passed Sherlock's room on his way to the bathroom, unsurprised to find the door closed. He showered quickly, before gathering all his laundry. Just then the doorbell rang, and John answered it, laundry bag slung over one shoulder. "Hello, John Watson? I'm from the laundry service; my name is Ann."

He handed the bag over and thanked her profusely, subtly scenting her. They _had_ sent a beta, he was pleased to note. After she left, he shut the door and turned on his heel.

Sherlock was standing in his dressing gown, fingers gripping the railing of the staircase. "I thought you'd left…" he explained, his grip loosening. He moved his hands over his dressing gown, smoothing it down, as his face once again became a hard mask of indifference.

"No, of course not, Sherlock. I'd tell you," John replied, a smirk working at the corner of his mouth. He walked past Sherlock up the stairs to his room, remembering his pills.

Later that day, John sat in the middle of the sofa, watching crap telly. Sherlock reclined on the right side of said sofa, his legs folded over the arm as he rested his head on John's lap. John absentmindedly stroked his hair, his back settling further into the couch as a commercial came on. "John?"

"Yes?" he replied, checking his phone for texts with his free hand.

"Put your mobile down. I have something important to say."

John complied, and his heart raced as he muted the TV. He looked down at Sherlock, fearing the worst: "I was mistaken, I don't want to be bonded" or "that was fine, but let's not do it again". He gulped, his throat suddenly very dry.

"John, I… I love you." John's breath caught in his throat.

He cleared his throat, and replied, "Sherlock, I love you too." He felt tears pricking in the corners of his eyes, but he didn't give in to it. He felt so relieved, he couldn't help but laugh. Sherlock's eyebrows raised, looking unamused.

"What is so funny, exactly?"

"You just nearly gave me a ruddy heart attack, that's all. I thought you were going to boot me."

Sherlock laughed, calling him a "mental omega". Slowly, their fits died down, until John was just looking down at him fondly.

"Never," he replied, smiling in return.

The next few weeks passed as they had before, with a few small changes. Sherlock took a liking to wearing his scarf indoors, and John opted for button-downs to hide his bond mark. What London didn't know wouldn't hurt it, they figured. They dashed about, continuing to foil criminals and stalk crime scenes.

But for one week every three months, they lay tangled in the sheets in one of their beds, giving in to their baser instincts. And though Sherlock might bemoan the occurrence, saying it "interfered with the work", John knew better. He'd cuddle against the smaller man in between bouts, neither willing to let go even though their skin burned up. He realized then that he'd never want anything else.


End file.
